Deltocyathus magnificus Moseley 1876

New Caledonia, 464-480 m (Kitahara & Cairns, 2009); east China sea, 88-422 m (Cairns 1994); western Pacific from Japan to southeastern Australia, 88-1500 m (Cairns & Zibrowius 1997); including Vanuatu region, 408-433 m (Cairns 1999); Sulu Archipelago, Moluccas, 118-1500 m; Philippines, Indonesia, 8-522 m (Cairns & Parker 1992); western Australia, 250 m (Cairns 2004).

Corallum discoidal to hexagonal with a slightly concave base. Costae equal thin ridges, finely dentate, being separated by wide furrows and extending up to 1 mm beyond calicular margin. C3-5 not present at centre of base. All costae laterally spinose especially near calicular edge, where intercostal furrows are deeper. Corallum white. Septa hexamerally arranged in 5 cycles (S1≥S2>S3>S4-5), but any specimen examined display a complete fifth cycle, denoting their juvenil stage. S1 only independent septa, 6 mm exsert, joining columella through a wide palus that sometimes are divided at the upper margin in 3 paliform lobes. S2 equal to slightly less wide than S1, also joining columella through a wide and tall pali. S3 4/5 width of S3, less exsert and bear a paliform lobe that fuses to P2 near columella. S4 half size of S3 and less exsert, joining P3 through a typical deltocyathid chevron arrangement. S5 less exsert but equal in width to S4, also bearing a paliform lobe that fuse P4. Fossa very shallow, aligned with the 2 principal and opposite S1, containing a papillose columella variable in size, shape, and number of rods.

Deltocyathus magnificus Moseley, 1876

Deltocyathus magnificus Moseley, 1876:552–553: 1881:147–148, pl. 4: fig. 10; pl. 13: figs. 1, 2.—Alcock, 1902c:20.—Yabe and Eguchi, 1937:138, pl. 20: figs. 13a—c, 14a–e.—Eguchi, 1938, table 2; 1942b: 126; 1965:286, 2 figs.—Utinomi, 1965:254.—Eguchi and Miyawaki, 1975:57.—Cairns and Parker, 1992:27–28, pl. 7: figs. j–l; pl. 8: fig. a.

DESCRIPTION.—Corallum discoidal, with a flat to slightly concave base that is not upturned at its edges. Largest Japanese specimen examined (Tsuchida-102) 30.0 mm in calicular diameter and 8.4 mm in height; however, Yabe and Eguchi (1937) reported a specimen 33.5 mm in diameter, and a specimen from the USNM collection from the Philippines (Alb-5444) measures 37.5 mm in diameter. Costae thin (0.2 mm), straight, finely serrate ridges separated by rather wide, flat intercostal spaces 3–4 times a costal width. All costae project about 1.5 mm beyond calicular edge and are continuous with their corresponding septa above. Corallum white; according to Moseley (1881), the coenosarc is ochre-yellow in color, somewhat red toward the margin, the polyps having white tentacles.

Septa hexamerally arranged in 5 complete cycles (96 septa), a juvenile 6.2 mm in calicular diameter having only 4 cycles, but a slightly larger corallum of 8.2 mm having all 96 septa. One large specimen (Tsuchida-102) has 2 S6, for a total of 98 septa. S1 are the only independent septa, joining the columella through a wide (about 4.5 mm) palus. S2 equal in height to S1 but slightly less wide, due to their even wider (about 6 mm) palus, which reaches to the columella. S3 also equal in height but considerably less wide, each bearing a broad palus that is connected to its adjacent P2 near the columella. S4 much lower in height than S1–3 and only 3–4 mm wide, but bordered internally by a broad palus that is fused to the adjacent P3 through a porous lamella. S5 least exsert septa but equally as wide as an S4, each S5 usually bordered by a narrow P5, each pair fused to the adjacent P4 through porous lamellae. Notch separating P5 from S5 sometimes quite broad or poorly formed, making the distinction of the P5 ambiguous. Fossa absent; columella an elongate fusion of irregular papillae.

azooxanthellate

88-1500 m